Snap action suction valve



Augo 1950 a F. KOUNOVSKY ETAL I 2,520,216

saw ACTION sucnou VALVE Filed Sept. 17, 1945 Patented Aug. 29, 1950 SNAP ACTION SUCTION VALVE Edward F. Kounovsky and John E. Dube, St. Louis,

Mo., assignors to Alco Valve Company, University City, Mo., a corporation of Missouri Application September 17, 1945, Serial No. 616,686

18 Claims.

The present invention relates to a snap action suction valv and especially to a valve of this kind that is temperature-responsive, and pilot operated.

It is an object of the invention to provide a valve of this type that is quick opening. A particular object is to provide such a valve that opens on rise in temperature for use in a refrigeration system, and operates so as to minimize short cycling of the compressor.

Another object is to provide such a valve as will give automatic defrosting f the evaporator for air temperatures above freezing.

Another object is to provide a valve having readily operable, compact, sealed, adjusting means, by which the temperature of operation may be regulated.

A further object is to provide a pilot operated valve of this type, with adjusting means, all compactly arranged for economy of construction and assembly, and of space occupied.

The drawing is an axial cross section of the valve.

The valve comprises a valv housing or body l0, having an inlet II and an outlet l2 separated by a partition l3 provided with the customary valve port l4 surrounded by an elevated, annular valve seat [5.

The Valve body In has a cylindrical bore l5 above the port l4 and co-axial therewith. The body l0 also has an annular flange l1 upstanding from its top surface, the flange having an inner cylindrical surface co-axial with, but larger than, the bore IS. A circular ledge l9 Joins the top of the bore IS with th bottom of the flange.

A flanged sleeve 20 is adapted to be inserted within the flange I1, and to have its flange supported by the ledge I9 01 the valve body. The sleeve extends slightly down into the bore l 6, provlding a shoulder 2i, and th sleeve is thereby stabilized and centered. It also has a depending cylindrical skirt 22, the outer surface of which is spaced inwardly from the bore I6. A cylindrical opening 23 extends through the sleeve 20 from top to bottom, and is slightly enlarged at the top. The sleeve 20 is removably held clamped to the valve body In by a flanged clamping ring 25, having a flang fitting within the flange ll of the valve body. Bolts clamp the parts together, and sealing is effected by the use of suitable gaskets, as shown.

The foregoing parts enclose a chamber for receiving a main valve and a pilot piston arrangement. The main valve member 21 is in th form of a piston cup, notched at its upper edge to prevent sealing off its interior from entering gas. It has a cylindrical side wall 28 freelyslidable within the bore it of the body Ill, and a bottom plug 29 secured thereto. The plug 29 holds lower and upper resilient valve closure inserts 30 and 3|, as well as a restrictor plug 32 that aids in holding th inserts, and depends substantially into the valve port I4. The plug 32 has a port 33 therethrough. This main valve member 2'! reciprocates vertically within the bore IE, to raise and lower the insert 30 from or to the valve seat I5.

A pilot piston 35 is shaped to reciprocate within the cylindrical opening 23 of the sleeve 20. This piston is cup-shaped, and has an inwardly tapered lower edge providing an annular valve seat 33 somewhat smaller in diameter than the piston itself. This piston 35 reciprocates within the cylindrical opening 23 toward and from the up opening 23 has permanently flxed therein a disc 31. This disc has a cylindrical guide stem38 extending upwardly therefrom. The lower surface of the disc 31 has an annular valve seat 39 projecting therefrom and surrounding a valve port 40 through the disc and part of the stem 38, to register with radial ports 4| opening above the sleeve 20. Above the radial ports, the opening is smaller.

A pilot valve disc 43 is secured to a pilot valve stem 44 that is guided for reciprocating movement in the stem 38, and project down below the pilot valve seat 39. The upper end of the stem 44 is secured into a buffer plate 45. A coil spring 46 surrounds the stem 38, and by engaging the disc 31 and the buffer plate 45, urges the latter upwardly, and the pilot valve disc 43 against its seat 39.

A bellows 49 fits over the buffer plate 45, and associated parts. At its lower end, the bellows is sealed to a ring 50.that is permanently united to a bellows enclosure 5|, the latter being permanently fixed into the ring 25. A separator plate 52 is permanently secured across the interior of the enclosure 5|, and has an opening therethrough to establish free communication above and below it.

The upper part of enclosure 5| receives an adjusting bellows construction. The adiusting bellows It is secured at its upper edge to a retainer plug I! initially screwed into the top of the enclosure 5i, but finally soldered thereto. The plug It has a portion depending within the bellows, and containing an adjusting screw it threaded therethrough. This screw is adapted to be engaged by a butler plate 51 within the bottom ofthe bellows 54, to limit the collapse of the bellows. The screw 58 projects above the plug It, and receives a pointer II fitted thereover to rest against a locating ring 59, and then fix d thereon. This pointer is adapted to engage a pin u pressed into the plug 85, which pin establishes the limits of rotation ofthe screw 56. The pointer 58 registers on a dial I centered in the enclosure Ii.

The dial is enclosed by a sealing cap 02 threaded onto the enclosure 5i and sealed by suitable gaskets.

Athermal bulb 85 is connected by a capillary ll into the enclosure ii. The bulb, capillary and enclosure are entirely filled with a solid charge of liquid having a low freezing point and a known coefilcient of thermal expansion.

A pilot port 68 leads from. the inlet side of the main valve, through a constriction ll, and into the cylindrical opening 23 above the pilot piston 35. The constriction is large enough to pas more gas than can leak by the piston ll or main valve member 21, and small enough so that the rate of gas flow through the valve port ll, when o en, is higher than that through the constriction. A bleeder port communicates from the radial pilot valve openings ii to the outlet side of the main valve.

Operation When the valve is closed, as shown, inlet side gas will be acting through the pilot passage 8! to the top of the pilot piston 2!. Owing to leakage around the pilot piston, inlet pressure will be acting downwardly within the main valve piston and on the pilot valve piston 35 over their entire upper surface areas. Inlet pressure will also act upwardly on the pilot piston over a small annular area defined by the outer periphery of the pilot piston, and the contact circle of the valve seat It. Inlet pressure will act directly upwardly on the main valve over an annular area defined by the outer periphery of the main valve, and the contact circle of the valve seat 15. Outlet pressure will act upwardly on the main valve piston over an annular area equal, net, to the difi'erence between the outermost bottom circle of the valve within the port it and the contact circle of the pilot piston seat 36. Outlet pressure will also act upwardly on the bottom of the pilot piston within the area of the seat 38. The diameter of the seat I! is greater than that of the seat 36.

Inlet pressure above the pilot piston and main valve is confined by the closed pilot valve, whose disc 43 is seated against the seat 39.

The net pressures aforesaid are such as to keep the main valve 21 seated, and to keep the pilot piston 35 down and seated on the insert ll.

Should the temperature at the bulb 85 increase, the liquid in the system will expand. This will first collapse the bellows 54 until its butler plate 51 is against the screw 56, and then will collapse the bellows 49 against the spring 46. This latter will open the pilot valve disc 43, permitting the inlet gas above the pilot piston to escape. The

. 4 the inlet through the constriction II, or the bleed past the pistons.

At the time the exhaust is efiectivethe pressure conditions on the main piston 21 are unchanged, as the leakage past the piston 35 is too slow to relieve the pressure above the main piston and below the edge of the pilot piston. However, the pilot piston is now subjected to this high pressure, and otherwise to low side pressure. The pilot piston thereupon rises, relieving the high pressure, which escapes through the port ll of the main valve. Relief of this pressure permits the main valve piston to rise under the influence of high pressure acting below its edge outside of the valve seat It.

When the main valve opens, it passes the gas through the port I4, a pressure drop accompanying the passage. The gas within and adjacent the port it will best an intermediate pressure, higher than that within the outlet i2, and hence higher than that acting above the pilot piston when the pilot valve is open. The member 32 projects into the port it to insure that the pressure conveyed to the upper side of the main valve piston 21 and the lower side of the pilot piston 35 will have this intermediate value.

This intermediate pressure will force the pilot piston all the way up. The main piston 21 will be forced up until its skirt 28 engages the shoulder 2i, by the difference between inlet pressure on its lower surface and the intermediate pressure on its upper surface. Preferably, the main piston does not rise far enough to contact the pilot piston.

Should the temperature at the bulb ii thereafter fall, the liquid will contract, and the spring 46 will close the pilot valve disc 43 against the seat 39. Inlet side pressure will then build up above the pilot piston as the constriction I admits more gas than can leak around the pistons, and inlet pressure then drives the pilot piston down against the main piston, and closes the valve seat 38 against the insert 3i. Then, leakage past the pilot piston I5 and the main piston 21 will cause inlet pressure to build up above the main piston, forcing it downwardly. The pilot piston and main pistons will both be moved downwardly until the main valve is closed.

If the temperature of operation is to be changed, the cap 62 is removed, and the screw it turned. If the screw is turned to expand the bellows it, it decreases the volumetric liquid capacity of the thermal system, causing the bellows 48 to be collapsed and the pilot valve opened by a lesser amount of expansion of the thermal liquid, and hence at a lower temperature. Conversely, withdrawal of the screw increases the liquid capacity and elevates the temperature of operation. The spring rate of the bellows It must be less .than that of the operating bellows assembly.

This valve is not designed to modulate or throttle, but rather to operate to either open or shut positions. Once the main valve starts to open, introducing intermediate pressure below the pilot piston, the latter rises its full distance, owing to the increased opening pressure then acting upon it. The valve opens on an increase in temperature, and remains fully open until the temperature decreases suiliciently to cause the valve to close. When used to regulate the fiow of gas from an evaporator in a refrigerant system, with the bulb responsive to temperature of the cooled fiuid, it will minimize short cycling of exhaust port system is substantially larger than 7 the compressor, and for air temperatures above freezing, will provide automatic defrosting oi the evaporator.

The pilot valve is permitted to overtravel a substantial distance in opening, so as to enable the screw 58 to be adjusted to lower the pilot valve closing temperature by maximum amounts.

This feature also prevents injury tothe structure in case 01' overheating of the bulb.

The disclosure of the drawing oilers advantages over a construction wherein the pilot piston is absent. Similar operating results can be obtained by making a device without the pilot piston and without the passage 33 through the main valve. Such arrangement requires a closely fitting main valve piston, whereas the present disclosure operates with a loose main.

partition, and an outlet, a main valve, a main piston connected for operating the main valve, a passage through the main piston, connecting the top side of the piston to the outlet side 01' the valve, a pilot piston, the lower side of the main piston being subjected to inlet pressure and having an effective pressure receiving area greater than that of the port, a control valve operated by the pilot piston to open and close the passage through the main piston, the pilot piston being subjected to the same pressure below it that acts on the top of the main piston and having a pressure receiving area greater than the size of the passage, the pilot piston being adapted to admit restricted flow of gas from above it to below it, constricted means independent of the position of the main valve, admitting inlet pressure to passage between and directly connecting the incylinder in the housing. extending beyond the portto provide a pressure receiving area to operate the piston subjected to inlet pressure, tending to open the main valve, a tubular portion extending from the main piston into the port for a substantial distance and adapted to provide a passage through the main piston connecting the outer side of the main piston with the port, a. pilot piston smaller than the main piston, disposed above the main piston and reciprocable within a cylinder on the housing, said pilot piston having parts adapted to seat on and close the passage through the main piston, constricted means admitting inlet pressure to the upper side or the pilot piston, more restricted passage means to admit inlet pressure below the pilot piston, above the main piston, said pilot piston being subjected to upward force 01 said inlet pressure below it for a limited area, and valve means to exhaust the pressure above the pilot piston.

4. In a valve construction, a housing, an inlet, an outlet, a partition between them, a portin the partition, a main valve controlling the port, and comprising a main piston reciprocable within a cylinder in the housing, extending beyond the port to provide a pressure receiving area to operate the piston subjected to inlet pressure, tending to open the main valve, a tubular portion extending from the main piston into the port for a substantial distance and adapted to provide a passage through the main piston connecting the outer side of the main piston with the port, a

let and space above the pilot piston, an exhaust v passage from above the pilot piston, a pilot valve to control the exhaust passage, means to open and close the pilot valve comprising a thermal bulb and expansible chamber, filled with liquid,

and means to adjust the volumetric capacity of v the chamber.

2. In a valve construction, a housing, an inlet,

an outlet, a partition between them, a port in the partition, a main valve controlling the port, and comprising a main piston reciprocable within a cylinderin the housing, extending beyond the port to provide a pressure receiving area to operate the piston subjected to inlet pressure, tending to open the main valve, a passage through the main piston connecting the outer side of the main piston with the port, a pilot piston above the main piston and reciprocable within a cylinder on the housing, said pilot piston having parts adapted to seat on and close the passage through the main piston, constricted means constantly connected with the inlet, admitting inlet pressure to the upper side of the pilot piston comprising an open restricted passage between and directly connecting the inlet and the space above the pilot piston, more restricted passage means to admit inlet pressure below the pilot piston, above the main piston, said pilot piston being subjected to upward force of said inlet pressure pilot piston smaller than the main piston, disposed above the main piston and reciprocable within a cylinder on the housing, said pilot piston having parts adapted to seat on and close the passage through the main piston, constricted means admitting inlet pressure to the upper side of the pilot piston, more restricted passage means to admit inlet pressure below the pilot piston, above the main piston, said pilot piston being subjected to upward force 01' said inlet pressure below it for a limited area, means to establish exhaust communication between the cylinder.

space above the pilot piston and the outlet side of the valve, and valve means to control the exhaust means.

5. In a valve construction, a housing, an inlet, an outlet, a partition between them, a port in the partition, a main valve controlling the port,

and comprising a main piston reciprocable within a cylinder in the housing, extending beyond the port to provide a pressure receiving area to operate. the piston subjected to inlet pressure, tend-- ing to open the main valve, a tubular portion extending from the main piston into the port for having parts adapted to seat on and close the' passage through the main piston, constricted means admitting inlet pressure tothe upper side a I of the pilot piston, more restricted passage means to admit inlet pressure below the pilot piston, above the. main piston, said pilot piston being subjected to upward force of said inlet pressure below it for a limited area, means to establish exhaust communication between the cylinder space above the pilot piston and the outlet side oi the valve, andvalve meansvto control the exhaust means, said valve means comprising a valve member movable with the pilot piston, and.

attains 7 the pilot piston being cup-shaped whereby the valve member may move within the pilot piston. 6. In a valve construction, a housing, anlnlet, an outlet, a partition therebetween, a port i i/the 8 of said pressure-responsive device being exposed to the inlet to receive high fluid pressure therefrom and having an eflective unbalanced pressure receiving area whereby said high fluid prespartition, valve mechanism to regulate 116W sure an displace the main valve, means for rethrough the port, including a bellows arranged stric y conducting said high fluid pressure to co-axlally above the port, an enclosur on the the er side of the pressure-responsive device housing to contain the bellows, pilot valv means wit in the main pressure chamber, an exhaust operated by collapse and expansion 0! th bel- Ir the main pressure chamber, to relieve preslows, a second bellows in the enclosure co-axiaiw ire therein derived from the restricted conductwith and above the flrst bellows, means adiusting means, a second pressure-responsive device ably fixingfife displacement oi the second beland a second valve operated thereby to control lows, and an expansible liquid within the ensaid exhaust,asecond pressure chamber 01' which closure and surrounding the two bellows, a cylinthe Sec d P p ve dev e is a wall der below the ilot valve, a loose fltting pilot is portion su j t d n i s inn s d t pr ssure piston therein, a continuously open restriction therein, the second pressure-responsive device directly connecting the inlet with the cylinder being subjected on its outer side to high pressure above the pilot piston, a main cylinder below derived from the inlet, means constantly conthe pilot cylinder and larger than the pilot cylinin the Second pressure chamber with the der, 9. main piston in the main cylinder and inlet and to exhaust, comprising passage means adapted to be acted upon by the gas leakage directly connecting the inlet, the second presaround the pilot piston, the main piston being sure chamber, and the exhaust, and a pilot valve adapted to' rest across and close the main port, controlling the passage means to regulate the and to overhang the same and thereby be subpressure in said second chamber, whereby when jected to'an opening influence oi. inlet pressure, 5 said pilot valve operates to reduce pressure in and a passage through the main piston to the the second pressure chamber, the second presoutlet side thereof, thepilot piston being adapted sure-responsive device will operate to open the to close said passage and to overhang the same second valve, exhausting pressure in the flrst to be subjected to upward influence of leakage pressure chamber, whereupon pressure acting on pressure above the main piston. the outside of the main pressure-responsive de- 7. In a valve having a housing with an inlet, an vice will operate the main valve, said main presoutlet, a partition therebetween, and a port sure-responsive device comprising a piston and through the partition, a main pressure-responthe first pressure chamber having a cylinder porsive device with a main valve controlling said tion in which the piston reciprocates. port operated thereby, a flrst pressure chamber 9. In a valve having a housing with an inlet, an of which the main pressure-responsive device outlet, a partition therebetween, and a port comprises a movable wall portion, the outer side through the partition, a main pressure-responof said pressure-responsive device being exposed sive device with a main valve controlling said to the inlet to receive high fluid pressure thereport operated thereby, a flrst pressure chamber from and having an effective unbalanced presof which the main pressure-responsive device sure receiving area whereby said high fluid prescomprises a movable wall portion, the outer side sure can displace the main valve, means for reof said pressure-responsive device being exposed strictedly conducting said high fluid pressure to to the inlet to receive high fluid pressure therethe inner side of the pressure-responsive device from and having an effective unbalanced preswithin the main pressure chamber, an exhaust sure receiving area whereby said high fluid presirom the main pressure chamber, to relieve pressure can displace the main valve, means for resure therein derived from the restricted oonductstrictedly conducting said high fluid pressure to ing means, a second pressure-responsive device the inner side of the pressure-responsive device and a second valve operated thereby to control within the main pressure chamber, an exhaust said exhaust, a second pressure chamber of which from the main pressure chamber, to relieve presthe second pressure-responsive device is a wall sure therein derived from the restricted conductportion subjected on its inner side to pressure ing means, a second pressure-responsive device therein, the second pressure-responsive device and a second valve operated thereby to control being subjected on its outer side to high pressure said exhaust, a second pressure chamber of which derived from the inlet, means constantly conthe second pressure-responsive device is a wall necting the second pressure chamber with the portion subjected on its inner side to pressure inlet and to exhaust, comprising passage means therein, the second pressure-responsive device directly connecting the inlet, the second pressure being subjected on its outer side to high preschamber, and the exhaust, and a pilot valve consure derived from the inlet. means constantly trolling the passage means to regulate the preson connecting the second pressure chamber with the sure in said second chamber, whereby when said inlet and to exhaust, comprising passage means pilot valve operates to reduce pressure in the directly connecting the inlet, the second pressecond pressure chamber, the second pressuresurechamber, and the exhaust, and a pilot valve responsive device will operate to open the seccontrolling the passage means to regulate the ond valve, exhausting pressure in the flrst presas pressure in said second chamber, whereby when sure chamber, whereupon pressure acting on the said pilot valve operates to reduce pressure in outside of the main pressure-responsive device the second pressure chamber, the second preswill operate the main'valve. sure-responsive device will operate to open the 8. In a valve having a housing with an inlet, an second valve, exhausting pressure in the flrst outlet, a partition therebetween, and a port pressure chamber, whereupon pressure acting on through the partition, a main pressure-responthe outside of the main pressure-responsive desive device with a main valve controlling said vice will operate the main valve, said main presport operated thereby, a flrst pressure chamber sure-responsive device comprising a piston and of which the main pressure-responsive device the flrst pressure chamber having a cylinder porcomprises a movable wall portion, the outer side 16 tion in which the piston reciprocates, said piston fittinginto said cylinder with a loose flt providing a clearance, the clearance comprising means to restrictedly conduct high fluid pressure to the inside of the first pressure chamber.

10. In a valve having a housing with an inlet, an outlet, a partition therebetween, and a port through the partition, a main pressure-responsive device with a main valve controlling said port operated thereby, a first pressure chamber of which the main pressure-responsive device comprises a movable wall portion, the outer side of said pressure-responsive device being exposed to the inlet to receive high fluid pressure therefrom and having an effective unbalanced pressure receiving area whereby said high fluid pressure can displace the main valve, means for restrictedly conducting said high fluid pressure to the inner side of the pressure-responsive device within the main pressure chamber,'an exhaust from themain pressure chamber, to relieve pressure therein derived from the restricted conducting means, a second pressure-responsive device and a second valve operated thereby to control said exhaust, a second pressure chamber of which the second pressure-responsive device is a wall portion subjected on its inner side to pressure therein, the second pressure-responsive device being subjected on its outer side to high pressure derived from the inlet, means constantly connecting the second pressure chamber with the inlet and to exhaust, comprising passage means directly connecting the inlet, the second pressure chamber, and the exhaust, and a pilot valve controlling the passage means to regulate the pressure in said second chamber, whereby when said pilot valve operates to reduce pressure in the second pressure chamber, the second pressure-responsive device will operate to open the second valve, exhausting pressure in the first pressure chamber, whereupon pressure acting on the outside of the main pressure-responsive device will operate the main valve, one of said pressure-responsive devices comprising a piston and its pressure chamber having a cylinder portion in which the piston reciprocates, there being a clearance in the cylinder outside the piston constituting the means to restrictedly conduct high pressure fiuld to the inside of the main pressure chamber.

11. In a valve having a housing with an inlet, an outlet, a partition therebetween, and a port throughthe partition, a main pressure-responsive device with a main valve controlling said port operated thereby, a first pressure chamber of which the main pressure-responsive device comprises a movable wall portion, the outer side of said pressure-responsive device being exposed to the inlet to receive high fluid pressure therefrom and having an effective unbalanced pressure receiving area whereby said high fluid can displace the main valve, means for restrictedly conducting said high fluid pressure to the inner side of the pressure-responsive device within the main pressure chamber, an exhaust fromthe main pressure chamber, to relieve pressure therein derived'from the restricted conducting means, a second pressure-responsive device and a second valve operated thereby to control said exhaust, a second pressure chamber of which the second pressure-responsive device is a wall portion subjected on its inner side to pressure therein, the second pressure-responsive device being subjectedon its outer side to high pressure derived from the inlet, means constantly connecting the second pressure chamber with the inlet and to exhaust, comprising passage means directly cont necting the inlet, the second pressure chamber,

- and the exhaust, and a pilot valve controlling the passage means to regulate the pressure in said second chamber, whereby when said pilot valve operates to reduce pressure in the second pressure chamber, the second pressure-responsive device will operate to open the second valve, exhausting pressure 'in the first pressure chamber, whereupon pressure acting on the outside of the main pressure-responsive device will operate the main valve, the main pressure-responsive device comprising a piston, and the first pressure chamber having a cylindrical portion in which the piston slides, the exhaust from the first pressure chamber comprising an opening through the piston and main valve to the outlet side of the main valve, the second valve being adapted to open and close said opening.

12. In a valve having a housing with an inlet, an outlet, a partition therebetween, and a port through the partition, a main pressure-responsive device with a main valve controlling said port operated thereby, a first pressure chamber 01' which the main pressure-responsive device comprises a movable wall portion, the outer side of said pressure-responsive device being exposed to the inlet to receive high fluid pressure therefrom and having an eil'ective unbalanced pressure receiving area whereby said high fluid pressure can displace the main valve, means for restrictedly conducting said high fluid pressure to the inner side or the pressure-responsive device within the main pressure chamber, an exhaust from the main pressure chamber, to relieve pressure therein derived from the restricted conducting means, a second pressure-responsive device and a secondvalve operated thereby to control said exhaust, a second pressure chamber of which the second pressure-responsive device is a wall portion subjected on its inner side to pressure therein, the second pressure-responsive device being subjected on its outer side to high pressure derived from the inlet, means con-- stantly connecting the second pressure chamber with the inlet and to exhaust, comprising a passagedirectly connecting the inlet, the second pressure chamber and the exhaust, and a pilot valve controlling the connecting means to regulate the pressure in said second chamber, whereby when said pilot valve operates to reduce pressure in the second pressure chamber,

the second pressure-respon ive device will operate to open the second valve, exhausting pressure in the first pressure chamber, whereupon pressure acting on the outside of the main pressure-responsive device will operate the main valve, and means to operate the-pilot valve in a gradual manner between its extreme positions sure receiving area whereby said high fluid pressure can displace the main valve, means for re strictedly conducting said high fluid pressure to the inner side 01' the pressure-responsive device within the main pressure chamber, an exhaust from the main pressure chamber, to relieve pressure therein derived from the restricted conducting means, a second pressure-responsive device and a second valve operated thereby to control said exhaust, a second pressure chamber of which the second pressure-responsive device is a wall portion subjected on its inner side to pressure therein, the second pressure-responsive device being subjected on its outer side to high pressure derived from the inlet, means constantly connecting the second pressure chamber with the inlet and to exhaust comprising a passage directly connecting the inlet, the second pressure chamber and the exhaust, and a pilot valve controlling the connecting means to regulate the pressure in said second chamber, whereby when said pilot valve operates to reduce pressure in the second pressure chamber, the second pressure-responsive device will operate to open the second valve, exhausting pressure in the first pressure chamber, whereupon pressure acting on the outside of the main pressure-responsive device will operate the main valve, thermostatic means to operate the pilot valve including a closed system containing an expansible fiuid, and means moved incrementally upon expansion and contraction of the fiuid, and means to transmit incremental movements of the moved means to the pilot valve.

14. In a valve construction, a housing having a high pressure inlet and a low pressure outlet, a valvlng partition between the inlet and outlet having a valve port therethrough, a main, first valve cooperating with the valve port, the valve Iii) port providing pressure reduction when flow 00- curs through the port, with an intermediate pressure zone adjacent the port on the outlet side of the valve, a first movable wall for operating the first valve, the movable wall having a first area subjected to inlet pressure tending to open the valve and a pressure chamber in which there is an opposite second area of the wall, with restricted communication from the inlet to the pressure chamber to introduce high inlet pressures restrictedly to the second area of the wall, an exhaust passage from the second area larger than the restricted communication to the second area, said passage extending to said intermediate pressure zone, a control valve controlling said passage, the control valve having a movable wall for its operation, one side or the movable wall of the control valve being subjected to the pressure in the pressure chamber of the main valve whenthe control valve is closed, and the control valve, when opened, opening said pressure chamber to the exhaust passage, a control valve pressure chamber on the opposite side of the movable wall 01' the control valve, the movable wall separating the pressure chambers, means directly restrictedly connecting the high pressure inlet side of the main valve to said control valve pressure chamber, an-exhaust for said control valve pressure chamber, and a pilot valve for controlling flow through the last named exhaust.

15. In a valve construction, a housing having a high pressure inlet and a low pressure outlet, a valving partition between the inlet and outlet having a valve port therethrough, a main, first valve cooperating with the valve port, the valve port providing pressure reduction when fiowoccurs through the port, with an intermediatepressure zone adjacent-the port on the outlet side or the valve, a first movable wall for operating the.

first valve, the movable wall having a first area subjected to inlet pressure tending to open the valve and a pressure chamber in which there is I 12 an opposite second area or the wall, with restricted communication from the inlet to the pressure chamber to introduce high inlet pressure restrictedly to the second area oi. the wall, an exhaust passage from the second area larger than the restricted communication to the second area, said passage extending to said intermediate pressure zone, a control valve controlling said passage, the control valve having a movable wall for its operation, one side of the movable wall of the control valve being subjected to the pressure in the pressure chamber of the main valve when the control valve is closed, and the control valve, when opened, opening said pressure chamber to the exhaust passage, a control valve pressure chamber on the opposite side of the movable wall or the control valve, the movable wall separating the pressure chambers, means directly restrictedly connecting the high pressure inlet side of the main valve to said control valve pressure chamber, an exhaust for said control valve pressure chamber, a pilot valve for controlling flow through the last named exhaust, and means responsive to changes in predetermined physical conditions for operating the control valve.

16. In a valve construction, a housing having a high pressure inlet and a low pressure outlet, a valvlng partition between the inlet and outlet having a valve port therethrough, a main, first valve cooperating with the valve port, the valve port providing pressure reduction when fiow occurs through the port, with an intermediate pressure zone adjacent the port on the outlet side of the valve, a first movable wall for operating the first valve, the movable wall having a first area subjected to inlet pressure tending to open the valve and a pressure chamber in which there is an opposite second area of the wall, with restricted communication from the inlet to the pressure chamber to introduce high inlet pressure restrictedly to the second area of the wall, an exhaust passage from the second area larger than the restricted communication to the second area, said passage extending to said intermediate pressure zone, a control valve controlling said passage, the control valve having a movable wall for its operation, one side of the movable wall of the control valve being subjected to the pressure in the pressure chamber of the main valve when the control valve is closed, and the control valve, when opened, opening said pressure chamber to the exhaust passage, a control valve pressure chamber on the opposite side of the movable wall of the control valve, the movable wall separating the pressure chambers, means directlyrestrictedly connecting the high pressure inlet side of the main valve to said control valve pressure chamber, an exhaust for said control valve pressure chamber, and a pilot valve for controlling ,fiow through the last named exhaust, eachj movable wall and its pressure chamber comprising a cylinder and a loosely fitting piston therein.

17. In a valve construction, a housing having a hi h pressure inlet and a low pressure outlet, 0. valvlng partition between the inlet and outlet havinga valve port therethrough, a main, first valve cooperating with the valve port, the valve port providing pressure reduction when fiow occurs through the port, with an intermediate pressure zone adjacent the port on the outlet side of the valve, a main cylinder in the housing, a main valve piston in the cylinder, the cylinder providing a pressure chamber on one side or the 13 piston,. to receive pressure tending to close the main valve, the piston on its opposite side being subjected to inlet pressure, tending to open the sure tending to close the control valve, means restrictedly admitting high .inlet pressure to the main cylinder pressure chamber at rates less than the exhaust capacityof thepassage through the main valve that is controlled by the control valve, means directly restricte'dly connecting the high pressure inlet to the control piston chamber, and an exhaust line for said control piston chamber of greater flow capacity than the said restricted admitting means, and pilot valve means controlling said exhaust line of the control piston chamber.

18. In a valve construction, a housing having a high pressure inlet and a low pressure outlet, a valving partition between the inlet and outlet having a valve port therethroughya main, first valve cooperating with the valve port, the valve port providing pressure reduction when flow occurs through the port, with an intermediate pressure zone adjacent the port on the outlet side of the valve, a main cylinder in the housing, a main valve piston in the cylinder, the cylinder providing a pressure chamber on one side of the piston, to receive pressure tending to close the main valve, the piston on its opposite side being subjected to inlet pressure, tending to open the main valve, a passage through the main valve and piston to exhaust the chamber to the intern mediate pressure zone of the housing, a control valve controlling said port and having an operat- -ing piston in the chamber which piston has an area subiected to said chamber pressure, tending 14 to open the control valve, a cylinder in which the control valve piston operates, and providing a control piston pressure chamber receiving pressure tending to close the control valve, means restrictedly admitting high inlet pressure to the main cylinder pressure chamber at rates less than the exhaust capacity of the passage through the main valve that is controlled by the control valve, means directly restrictedly connecting the high pressure inlet to the control piston chamber, and an exhaust line for said control piston chamber of greater flow capacity than the said restricted admitting means, and pilot valve means controlling said exhaust line of the control piston chamber, said last named pilot valve means including a mechanism movable in response to predetermined physical conditions and a pilot valve operated thereby.

EDWARD F'. KOUNOVSKY. JOHN E. DUBE.

REFERENCES CITED The following references are of record in the file 01' this patent:

UNITED STATES PATENTS Number Name Date 629,789 Honiball Aug. 1, 1899 1,031,913 Casse July 9, 1912 1,254,869 Watrous Jan. 29, 1918 1,540,267 Langston June 2, 1925 1,794,640 Owens Mar. 3, 1931 1,850,354 Owens Mar. 22, 1932 1,925,530 Gotthardt Sept. 5, 1933 2,013,480 Sandvoss Sept. 3, 1935 2,264,261 Erbguth Nov. 25, 1941 2,321,743 Guibert June 15, 1943 ,416,875 Kehoe Mar. 4, 1947 FOREIGN PATENTS Number Country Date 490,081 Great Britain Aug. 9, 1938 582,088 Germany Aug. 8, 1933 833,361 France July 18, 1938 

